1. Field of the Invention
The present invention relates generally to nozzles, and in particular, is concerned with a supersonic fan nozzle having guide plates or deflectors for providing a broad exit swath.
2. Description of the Related Art
Supersonic nozzles are well-known in the art. Conventional venturi-type nozzles include a converging section, a throat and a diverging section. If sufficient pressure is applied to a venturi-type nozzle, air velocity at the throat will become sonic, and then increase as the air expands at the diverging section to produce a supersonic outlet velocity. The exact exit velocity depends on air pressure, size and other details of the nozzle design. Such nozzles are readily commercially available.
Various nozzle designs have been incorporated in sand blasting applications. Air and sand are mixed and discharged through a nozzle. Representative examples of sand blasting and spraying nozzles are found in U.S. Pat. No. 773,665; 990,409; 1,326,913; 1,410,117; 2,341,036; 2,605,596; 2,606,073; 4,038,786; 4,389,820 and 4,633,623.
The discharge pattern from many commercially available nozzles is circular or round. In order to obtain a uniform cleaning pattern on a surface, it is necessary to have considerable overlap of the discharge, sometimes by as much as fifty percent. Such overlap is time-consuming and uneconomical. Fan-shaped nozzles have also proved inadequate because of rapid erosion of internal passages Such erosion requires frequent nozzle replacement.
It is known in the art to discharge carbon dioxide pellets from a spray nozzle in a cryogenic cleaning apparatus. Such a method and apparatus are disclosed in U.S. Pat. No. 4,617,064 issued in 1986 to a co-applicant of this invention.
Consequently, a need exists for improvements in discharge nozzles utilized with cleaning devices. It is desirable that a discharge nozzle provide a supersonic outlet velocity and a wide cleaning swath. It is also desirable that the nozzle be durable and long lasting.